From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B7928253954; Mon, 13 Oct 2025 15:10:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760368254; cv=none; b=F/EY9OAeRDF1wS/rD9WahfnlnOH5yY0t7cYxH8o4R+rqVu6yAoeRp8KFP+SWAqt8j7NduwcmO1qTYMEyRG990ZBEbf3KJiY3yXlD97sFL00G75JSxzvklt53p78/vX/ZmRGnw/6tn6pQIw+HbJ3BJx3E6IYNlgg6pY+691Fcz3k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760368254; c=relaxed/simple; bh=pdKTKvxteNA7xF7K5zhRqv2tcuvInOQ67q0xLBCrzQI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NiwaMuA3J+9UgGoKaGwu3/PSbT1tYUusDn+DSPY18qUYHjbpwRru2v6DibpfrAqiERW6h+f8tO/GcktrYM7eYs2Djk+S7wpJdnM3tts5LZpw2sThLdRVJfYbsGWsEaK0949VgNE76l0ZM885Zg0+NmBYfBOjk4KN/SnSZ9esP3w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=VU17hVYX; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="VU17hVYX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3C30FC4CEE7; Mon, 13 Oct 2025 15:10:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1760368254; bh=pdKTKvxteNA7xF7K5zhRqv2tcuvInOQ67q0xLBCrzQI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VU17hVYX1+40X0c6pDRNqtOTvdUrE5qx6HcNvhmz85PRAxpVGZ+2hIH2dUsqeNQyY bFKNYHykOK9R1Ldt1LVsctujB8FfHm4pbr1/MOaB6IOwKLhHs14KpdFfA1hQqqCoSi ma/80/GrWfYTcfDLQvZZ7MCcC70U+wei+uDvnzIk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Hengqi Chen , Daniel Borkmann , Pu Lehui , Sasha Levin Subject: [PATCH 6.12 070/262] riscv, bpf: Sign extend struct ops return values properly Date: Mon, 13 Oct 2025 16:43:32 +0200 Message-ID: <20251013144328.648524812@linuxfoundation.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251013144326.116493600@linuxfoundation.org> References: <20251013144326.116493600@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Hengqi Chen [ Upstream commit fd2e08128944a7679e753f920e9eda72057e427c ] The ns_bpf_qdisc selftest triggers a kernel panic: Unable to handle kernel paging request at virtual address ffffffffa38dbf58 Current test_progs pgtable: 4K pagesize, 57-bit VAs, pgdp=0x00000001109cc000 [ffffffffa38dbf58] pgd=000000011fffd801, p4d=000000011fffd401, pud=000000011fffd001, pmd=0000000000000000 Oops [#1] Modules linked in: bpf_testmod(OE) xt_conntrack nls_iso8859_1 [...] [last unloaded: bpf_testmod(OE)] CPU: 1 UID: 0 PID: 23584 Comm: test_progs Tainted: G W OE 6.17.0-rc1-g2465bb83e0b4 #1 NONE Tainted: [W]=WARN, [O]=OOT_MODULE, [E]=UNSIGNED_MODULE Hardware name: Unknown Unknown Product/Unknown Product, BIOS 2024.01+dfsg-1ubuntu5.1 01/01/2024 epc : __qdisc_run+0x82/0x6f0 ra : __qdisc_run+0x6e/0x6f0 epc : ffffffff80bd5c7a ra : ffffffff80bd5c66 sp : ff2000000eecb550 gp : ffffffff82472098 tp : ff60000096895940 t0 : ffffffff8001f180 t1 : ffffffff801e1664 t2 : 0000000000000000 s0 : ff2000000eecb5d0 s1 : ff60000093a6a600 a0 : ffffffffa38dbee8 a1 : 0000000000000001 a2 : ff2000000eecb510 a3 : 0000000000000001 a4 : 0000000000000000 a5 : 0000000000000010 a6 : 0000000000000000 a7 : 0000000000735049 s2 : ffffffffa38dbee8 s3 : 0000000000000040 s4 : ff6000008bcda000 s5 : 0000000000000008 s6 : ff60000093a6a680 s7 : ff60000093a6a6f0 s8 : ff60000093a6a6ac s9 : ff60000093140000 s10: 0000000000000000 s11: ff2000000eecb9d0 t3 : 0000000000000000 t4 : 0000000000ff0000 t5 : 0000000000000000 t6 : ff60000093a6a8b6 status: 0000000200000120 badaddr: ffffffffa38dbf58 cause: 000000000000000d [] __qdisc_run+0x82/0x6f0 [] __dev_queue_xmit+0x4c0/0x1128 [] neigh_resolve_output+0xd0/0x170 [] ip6_finish_output2+0x226/0x6c8 [] ip6_finish_output+0x10c/0x2a0 [] ip6_output+0x5e/0x178 [] ip6_xmit+0x29a/0x608 [] inet6_csk_xmit+0xe6/0x140 [] __tcp_transmit_skb+0x45c/0xaa8 [] tcp_connect+0x9ce/0xd10 [] tcp_v6_connect+0x4ac/0x5e8 [] __inet_stream_connect+0xd8/0x318 [] inet_stream_connect+0x3e/0x68 [] __sys_connect_file+0x50/0x88 [] __sys_connect+0x96/0xc8 [] __riscv_sys_connect+0x20/0x30 [] do_trap_ecall_u+0x256/0x378 [] handle_exception+0x14a/0x156 Code: 892a 0363 1205 489c 8bc1 c7e5 2d03 084a 2703 080a (2783) 0709 ---[ end trace 0000000000000000 ]--- The bpf_fifo_dequeue prog returns a skb which is a pointer. The pointer is treated as a 32bit value and sign extend to 64bit in epilogue. This behavior is right for most bpf prog types but wrong for struct ops which requires RISC-V ABI. So let's sign extend struct ops return values according to the function model and RISC-V ABI([0]). [0]: https://riscv.org/wp-content/uploads/2024/12/riscv-calling.pdf Fixes: 25ad10658dc1 ("riscv, bpf: Adapt bpf trampoline to optimized riscv ftrace framework") Signed-off-by: Hengqi Chen Signed-off-by: Daniel Borkmann Tested-by: Pu Lehui Reviewed-by: Pu Lehui Link: https://lore.kernel.org/bpf/20250908012448.1695-1-hengqi.chen@gmail.com Signed-off-by: Sasha Levin --- arch/riscv/net/bpf_jit_comp64.c | 42 ++++++++++++++++++++++++++++++++- 1 file changed, 41 insertions(+), 1 deletion(-) diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c index 563425b4963c9..497945aa3e2c4 100644 --- a/arch/riscv/net/bpf_jit_comp64.c +++ b/arch/riscv/net/bpf_jit_comp64.c @@ -559,6 +559,39 @@ static void emit_atomic(u8 rd, u8 rs, s16 off, s32 imm, bool is64, } } +/* + * Sign-extend the register if necessary + */ +static int sign_extend(u8 rd, u8 rs, u8 sz, bool sign, struct rv_jit_context *ctx) +{ + if (!sign && (sz == 1 || sz == 2)) { + if (rd != rs) + emit_mv(rd, rs, ctx); + return 0; + } + + switch (sz) { + case 1: + emit_sextb(rd, rs, ctx); + break; + case 2: + emit_sexth(rd, rs, ctx); + break; + case 4: + emit_sextw(rd, rs, ctx); + break; + case 8: + if (rd != rs) + emit_mv(rd, rs, ctx); + break; + default: + pr_err("bpf-jit: invalid size %d for sign_extend\n", sz); + return -EINVAL; + } + + return 0; +} + #define BPF_FIXUP_OFFSET_MASK GENMASK(26, 0) #define BPF_FIXUP_REG_MASK GENMASK(31, 27) #define REG_DONT_CLEAR_MARKER 0 /* RV_REG_ZERO unused in pt_regmap */ @@ -1020,8 +1053,15 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, restore_args(min_t(int, nr_arg_slots, RV_MAX_REG_ARGS), args_off, ctx); if (save_ret) { - emit_ld(RV_REG_A0, -retval_off, RV_REG_FP, ctx); emit_ld(regmap[BPF_REG_0], -(retval_off - 8), RV_REG_FP, ctx); + if (is_struct_ops) { + ret = sign_extend(RV_REG_A0, regmap[BPF_REG_0], m->ret_size, + m->ret_flags & BTF_FMODEL_SIGNED_ARG, ctx); + if (ret) + goto out; + } else { + emit_ld(RV_REG_A0, -retval_off, RV_REG_FP, ctx); + } } emit_ld(RV_REG_S1, -sreg_off, RV_REG_FP, ctx); -- 2.51.0